DTC P0172: System Too Rich (Bank 1)

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

P0172 - SYSTEM TOO RICH (BANK 1)

Description:	The adaptive fuel strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a lean calibrated limit. Refer to POWERTRAIN CONTROL SOFTWARE , FUEL TRIM for more information.
Possible Causes:	Fuel System: Damaged or leaking fuel pressure regulator on fuel pump module Leaking fuel injectors EVAP canister purge valve is leaking when the canister is full Base Engine: Engine oil contamination Intake Air System: Damaged or contaminated mass air flow (MAF) sensor
Diagnostic Aids:	View the freeze frame data to determine the operating conditions when the DTC was set. Observe the LONGFT1 PID. Refer to ADAPTIVE FUEL DIAGNOSTIC TROUBLE CODE (DTCS) DIAGNOSTIC TECHNIQUES , for more information and the appropriate pinpoint test for specific concern identification.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
All	GO to PINPOINT TEST H .